Who she is: Mystique, a.k.a. Raven
Her power: Mystique is a shape-shifter who can alter her appearance and voice to look and sound like any human. She’s also extremely agile.
Her story: The scaly, blue, minimally clothed Mystique is completely attached to Magneto when she’s first introduced in the XMU. In X-Men, she kidnaps Senator Kelly, contaminates Cerebro, and fights the Charles Xavier’s heroic mutant team, and she’s the only member of Magneto’s Brotherhood to stick around in X2. She helps break Magneto out of his glass prison in that film, and the two of them team up with the X-Men to stop Major William Stryker’s plot to annihilate mutants. Her final present-day appearance is in X-Men: The Last Stand, and despite Mystique’s loyalty throughout the trilogy, Magneto abandons her when she’s injected with Worthington Labs’ mutant cure.
Mystique becomes a major player in the XMU when the timeline jumps backward for X-Men: First Class, revealing that Mystique was Charles Xavier’s childhood best friend back when she went by Raven. They meet in 1944, and she remains by his side as he becomes an accomplished geneticist and partners with Erik Lehnsherr to create a C.I.A.-sanctioned team of young mutants. Taking on the mutant name Mystique, Raven learns to accept her mutation thanks to Erik’s influence, and she decides to join his Brotherhood at the end of the movie instead of sticking with Charles and her new beau, Hank McCoy. With Magneto in prison, Mystique is on her own in X-Men: Days Of Future Past, and Wolverine stops her from creating a future dystopia by preventing her from assassinating Bolivar Trask, creator of the mutant-hunting Sentinels. Mystique becomes a mutant hero when she stops Magneto from killing President Nixon, and in X-Men: Apocalypse, she travels the world rescuing mutants who are persecuted for their biology. She joins the X-Men to take out the threat of Apocalypse and his horsemen, and when the dust settles after the big fight, Mystique has firmly shifted her alliance back to Charles.
Played by: Morgan Lily (child) in X-Men: First Class; Jennifer Lawrence (adult) in X-Men: First Class, X-Men: Days Of Future Past, and X-Men: Apocalyse; Rebecca Romijn in X-Men, X2, X-Men: The Last Stand, and X-Men: First Class.
Currently, Mystique is: A member of the X-Men and most likely a professor at Xavier’s School For Gifted Youngsters.
Where will we see her next? Expect Mystique to appear in the next X-sequel, although she may be recast, considering Jennifer Lawrence has been publicly hesitant about her commitment to the character’s future. As long as there are actors willing to cover themselves in head-to-toe prosthetics and makeup, there will be more Mystique in the XMU.